In an electrophotographic type image forming apparatus, a structure is known in which the rotatable elements such as a photosensitive drum or developing roller relating to image formation are contained in the cartridge which is detachably mountable to a main assembly of the image forming apparatus.
Such an image forming apparatus requires maintenance operations for some elements. In order to facilitate the maintenance operation for various process means, the above-described photosensitive drum, charging means, developing means, cleaning means and so on are contained in a frame to form a cartridge. By making the cartridge detachable and mountable relative to the image forming apparatus, the maintenance operations are easy.
In such a cartridge type device, a structure is known in which untransferred toner (residual toner) resulting from a cleaning process during the image forming operation is retained in the cartridge.
In addition, Japanese Laid-open Patent Application 2014-52475 discloses a structure in which residual toner resulting in the cleaning process during the image forming operation is fed into a residual toner accommodating portion provided in the main assembly.